Influence of surface oxide layer of SiC powder on the rheological properties of its slurry

Abstract

In this paper, the influence of surface oxide layer of SiC powder on the rheological behavior of its slurry was studied by acid washing, HF etching, and calcination oxidation processes. Zeta potential, particle size, inductively coupled plasma atomic emission spectrometry (ICP‐AES), energy dispersive X‐ray spectroscopy, and viscosity tests indicated the main factor that resulted in high viscosity of slurry is impure ions existing either on the powder surface or in the water phase, rather than the surface oxide layer. After the impure ions are removed, the surface oxide layer formed at a calcination temperature range of 400°C‐750°C does not cause an increase in the slurry viscosity, but contributes to an improvement in the rheological properties of SiC slurry.

Enhancing Compressive Strength of Reticulated Porous Alumina by Optimizing Processing Conditions

“…The variation in the average alumina particle size affects the morphology of the strut walls of the reticulated porous alumina as shown in Figure 3a-c solid loading alumina slurry with moderate viscosity, we attempted to determine the optimal processing conditions; especially, solid loading, average particle size, binder, and dispersant. Although several approaches to obtain an extremely high solid loading have been reported by surface modification [35,36], it is beyond the scope of this work. To vary the average particle size of the alumina particles, fine, intermediate, and coarse alumina was used.…”

High‐temperature strength of liquid‐phase‐sintered silicon carbide ceramics: A review

“…28,[85][86][87][88][89] These additives form oxycarbide or oxycarbonitride melt by reacting with SiO 2 (always present on the surface of SiC particles) and nitrogen atmosphere during sintering, which remained at the grain boundary as an IGF and at the three-grain pocket as a junction phase after sintering. 57 Gao et al 90 reported that commercially available SiC powders inherently contain ~2% of various impurities including SiO 2 . In this review, the grain-boundary structure of LPS-SiC ceramics is classified into three different boundaries based on the crystallinity and presence of IGF: amorphous grain boundaries (containing amorphous IGF), crystallized grain boundaries (containing crystalline IGF), and clean grain boundaries (IGF free with some element segregation).…”

Sintering β-SiC nanopowder using novel microwave-current assisted sintering technique: preliminary study

“…The percentage of oxide removal in the treated powder was 72% using HF. While, it was 11% using HCL [10]. However, the chemical treatment of SiC powder can achieve a high percentage of purity using HF and HCL.…”